bdb Posted December 18, 2007 Share Posted December 18, 2007 This is one color management issue I still don't fully understand. Whenprinting to an Epson R2400 in a color-managed workflow (from Lightroom andPhotoshop CS3), should I be selecting Perceptual or Relative? And should Iselect black point compensation (it is automatically selected in Lightroom, itseems). Link to comment Share on other sites More sharing options...
patricklavoie Posted December 18, 2007 Share Posted December 18, 2007 1_i didtn see much difference myself, but i read that relative gave better result. 2_yes in both case. or i should say always if you can. Link to comment Share on other sites More sharing options...
peter_mounier Posted December 18, 2007 Share Posted December 18, 2007 When you have an out of gamut color in your image, the relative colorimetric rendering adjusts just that one out of gamut color so that it is in gamut by picking the closest color to it that is in gamut. The perceptual rendering adjusts all the colors in your image so that the relationship between all the colors remains the same. To me that means that if I use perceptual rendering the colors might all change unpredictably. If I use relative rendering, the only color that might change unpredictably will be the out of gamut color. Peter Link to comment Share on other sites More sharing options...
inspiration point studio Posted December 18, 2007 Share Posted December 18, 2007 Most people defaults to Relative. Another approach is before you print the image, you can use the soft proofing feature to see how the print out will look, you can switch between relative and perceptual to gauge which one you like better. Link to comment Share on other sites More sharing options...
godfrey Posted December 18, 2007 Share Posted December 18, 2007 Differences between how relative colormetric and perceptual will render an image depends a lot on the specific image dynamics. Most images will look virtually identical, but if the color values are approaching boundaries of the output paper-ink profile, you might see differences. <br><br> There's a decent write up of Rendering Intents at Steve's Digicams: <br> <a href="http://steves-digicams.com/techcorner/July_2005.html" target=new> http://steves-digicams.com/techcorner/July_2005.html</a><br> <br> My default is to use relative colormetric with black point compensation enabled. It produces very nice results on the R2400 from Lightroom. <br><br> Godfrey <br> Link to comment Share on other sites More sharing options...
bruce_watson1 Posted December 18, 2007 Share Posted December 18, 2007 Quick search on the 'net found this: http://www.cambridgeincolour.com/tutorials/color-space-conversion.htm Tells you everything you need to know. Link to comment Share on other sites More sharing options...
KenPapai Posted December 19, 2007 Share Posted December 19, 2007 I print a ton to the R2400 from Photoshop and almost ALWAYS choose Black Pt. Compensation and Perceptual. There you are. It works, tried and true. Link to comment Share on other sites More sharing options...
teeuwen Posted December 19, 2007 Share Posted December 19, 2007 > 2_yes in both case. or i should say always if you can. The majority of the paper profiles incorporate a perceptual rendering intent that tries to make use of the whole dark range of the media, by definition. Therefore, since it already maps the dark colors of the media, enabling BPC does not affect this rendering intent much... almost always. Quote from "Adobe Systems' Implementation of BPC" http://partners.adobe.com/public/developer/en/pdf/AdobeBPC.pdf "Color conversion using Perceptual intent already maps source white to destination white and source black to destination black. Because this mapping preserves the relationships of the shades, it is unlikely that a whole shadow section will be mapped to the same black value. Therefore, BPC should not be necessary. BPC is available, however, for this rendering intent, to be used with malformed profiles. For a given picture, the user can decide whether using BPC improves the color conversion and can select it or deselect it accordingly." Link to comment Share on other sites More sharing options...
erik scanhancer Posted December 19, 2007 Share Posted December 19, 2007 Always use perceptual renedering with blackpoint compensation for printing. Printer profiles are made for perceptual rendering by default. In order to avoid unexpected color shifts you should use softproofing and make sure that the out of gamut colors are brought within gamut (best method is selective desaturation until they are safe). Relative rendering should be used for converting from one color space to another, not for printing. Link to comment Share on other sites More sharing options...
teeuwen Posted December 20, 2007 Share Posted December 20, 2007 > Printer profiles are made for perceptual rendering by default. Please explain? > ... make sure that the out of gamut colors are brought within gamut The essence of perceptual gamut mapping is (fixed) gamut compression of ALL colors (out-of-gamut + in-gamut). So why bother bringing out-of-gamut colors within gamut when using perceptual? > Relative rendering should be used for converting from one color space to another Relative colorimetric is the ONLY intent that will be applied when doing working space (matrix) conversions. It's not the only option you have in PS, perceptual is not grayed out, but PS WILL do a relative conversion. Link to comment Share on other sites More sharing options...
erik scanhancer Posted December 23, 2007 Share Posted December 23, 2007 "> Printer profiles are made for perceptual rendering by default. Please explain?" - That's the rendering intent almost all profiling software expects to be used for printer profiles. Open up a printer profile and check what rendering intent it was made for. You'll notice it was made for perceptual rendering 99 out of 100 times. "> ... make sure that the out of gamut colors are brought within gamut The essence of perceptual gamut mapping is (fixed) gamut compression of ALL colors (out-of-gamut + in-gamut). So why bother bringing out-of-gamut colors within gamut when using perceptual?" - This way you have manual control over how the out-of-gamut colors are being rendered, while the other colors are still rendered the way the profile was designed for. "> Relative rendering should be used for converting from one color space to another Relative colorimetric is the ONLY intent that will be applied when doing working space (matrix) conversions. It's not the only option you have in PS, perceptual is not grayed out, but PS WILL do a relative conversion." - Yes, and I was briefly explaining why that is. Link to comment Share on other sites More sharing options...
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